OK so I have got myself a Silverstone Tundra TD3 water pump and replaced my faulty pump.
Unfortunately it is not much better than the cheap Cooler Master Seidon 120 that I've tried a few days ago...
Both could solve my problem, partially. With the replacement pump I can now mine with all 16 cores, but only if set to Power Step 6. many chips shuts as soon as I step up to Power Step 7. Probably the pump is not strong enough to remove the heat???
The pump speed only reads 1200 RPM for TD3, while it's ~1000 RPM for Seidon 120. Noticed that the original cointerra pumps are 3000 RPM ...
Any idea on how I could boost the replacement pumps so that I could fully utilize my miner to Step 9 again? Maybe Liquid Pro could help? I am using Artic Silver 5 for thermal paste now.
LP will likely drop your temps a few more degrees. But be very careful when applying the stuff. Unlike AS5 it's electrically conductive. So it can short out your board if it gets in the wrong place.
Stuff is like (and likely contains quite a bit of) liquid mercury. This thread has lots of good info on how to go about applying.
Also, your chips shouldn't shut down at PL7 unless they're getting above 120C.
Lastly, when you applied AS5 did you also apply it to the square "ring" that surrounds the chips. I'm pretty sure you do not need to apply there. My hunch is that doing so "lifts" the cooling block ever so slightly off the chips.
Several have speculated that the chips suffer from some misalignment in the horizontal plane ... which makes for tricky cooling issues and thermal paste application that lots have been experiencing.
But it sounds more like you need better pumps. Also, what's your intake air temp? IE., the temp in the room. I've found if it's above 80F everything starts to overheat. Below that and things are fine.